Production of glycerin by fermentation



,. 36 the v I comethis difliculty,

- and dropping of rapidly Patented Aug. 20, 1929.

I 1,725,361 UNITED STATES PATENT OFFICE.

13am: A, mcnnnmo'rn'or cnamon'r, DELAWARE,

ASSIGNOR TO E. I. DU POINT DE NEMOURS AND COMPANY, 01" WILMINGTON, DELAWARE, A CORIEQRATION OF nnnawann Io Drawing.

of such salts or alkaline substances dissolved 1n an aqueous solution of' a fermentable sugar, and particularly in an aqueous sugar .10 solution whose sugar content is about the same as that of the mash undergoing fermentation.

In the course of my work on the production of glycerin b fermentation I perceived 16 the desirability developing a satisfactory method for adding the alkali (e. g. soda ash) in solution instead of the solid form. If

this could be done it would tion of adding the soda ash much less oh- I), jectionable than at present as the light ash tends to dust very readily and in consequence not only is there a loss ofash owing to the material thus escaping from the mixing apparatus, but'the air of the rooms in which the soda mixing appa'ratus is located is so full of soda dust as to make objectionable to work in, most of the operators finding the use of dust masks necessary. However, all fermentations previit extremely ously made in which the soda has been added in solution instead of in the solid form have consistently given lower yields of lglycerin than the controls run according to t e usual procedure, andin some cases a decrease in yield of both alcohol and glycerin has been noted. Attempts were made to overwhich appeared to be due to the dilution of the mash by the soda solution, by a reduction in the initial vol- 40 ume of. the mash, while using the same amount of molasses, the reduction in the volume being equivalent to the amount of water,

' used in making'the soda solution. Better results were not obtained by this modification however, and ithas generally been assumed that the soda ash could not be added in so-- lution with as satisfactory'results in so far asthe yield from the fermentation is concerned as when the soda is added in solid form,"

It may be noted that the solubility of so dium carbonate in water reaches a maximum of about 45% being somewhat less at higher temperatures at lower temperamake the operasoda in a'solution o cally it above 30 I weight of 'mash in each at about 40 0., the solubility .rnonucrronor GLYCERIN :sY rrimrnnrflron. Application filed November-'7, 1922. Serial No. 599,574.

tures/ As our fermentations are run at a temperature of about 3035 C." it has not been considered practical to use amore concentrated solution than 40%,held at-a temperature of 30 C., and any material evaporation from this zation of soda.

Apparently the chief factors tending to reduce the yields with the above-mentioned modified process are the change in concentration of the solution resulting from the ad.- dition of the soda solutionin'thecase of meshes made in the usual way, and the slower fermentation and generally unfavorable effect of the higher concentration of sugar, etc., at the-start, when the meshes are made up more concentrated than for the usual method. j It occurred to me that it might be ossible to avoid the dilution and resulting ecreajsein 'eld by dissolving the concentration as the initial mash; In preliminary experiments 'I found that a solution of 300 g; of molasses in 700 cc. of water will dissolve 300 g. of anhydrous sodium carbonate and retain the latter in solution at 30 C. or even somewhat lower; practi is advantageous to dissolve the soda in the water at a temperature somewhat C.even as high as 50 C.-and then to add themolasses when the solution has cooled to between about 30 and 35 C. Such solutions are apparently fairly stable at the temperatures at which they are used, around 30 0., and showed no evidence of serious decomposition; there was a slight precipitation and the development of a slight ammoniacal odor. Nef is said to have stated that an alkaline solution of glucose may contain as. many as 128 difierent substances, and it'is known that glucose is destroyed quite rapidly in hot alkaline soluti but as'more'than half of the sugar in cane molasses is probably sucrose, which is not readily destroyed under these conditions,

there would be no great reduction in the peri centage of fermentable su gar resent. .To illustrate my invention shall describe four typical experiments which have been run in accordance with this process, the final v experiment being 8 ln'los. In each of these e eriments there was used an initial mash o 7200 grams of 30% black strap molasses solutioncontaining 0.5% of ammonium sulfate; of this amount,

solution results in crystalli-- molasses. of the same" 6165 g'.. were placed in a flask and sterilized, while the remaining 1035 grams were placed in another flask, sterilized, cooled and to the coolsterile solution was then added (in exof vigorous fermentation following the pm oading dose-of the alkaline. molasses solution. The results obtained "on the analysis of the fermented liquor in these four experi-' ments are shown "on the following table:

TABLE 1. Y

. Grams Final Total 7 7 '7 No. muh suar resld. 81? a e.

' seeded mash Q orig. sugar by wt. by wt.

1 8000 112a 1. 12 14.11 1. m 4.88 3.40 2 am ms 1.083 1111 1.50 4.93 3.30 a soon I ma 1.056 14.11 1% 5.10 3.42 Q m '1128 LG 14.11 1.07. 5.07 3.30

TABLE I (Cont);

mt-1 u 7 ottermsnted sugar mm toconveitml toby by 0%) v Glycerin Wm?) by wt.

are 24, 1 5&1 38.9 21.2 66.1 35.0 23.8 58.8 as. 1 28.6 65.7 sec 24.2 00.4 39.1 26.6 are aao 23.4 50.4 38.9 25.3 ,ota

It is., obvious that the results need not be confined to sodium carbonate out otassium carbonate'orother alkaline salts o sufiicient l tf mflybe used instead, orsoluble salts, whether 'a llmlinej dr no't, such as'thosb which maybe recovered. from. the ash of molasses asdescribed in theapplication of J. W.,Law'rie, Serial No. 577,992, may be employed. Furthermore, instead of yeast N0. v16, described in detail n my patent 1,551,997 issued September 1,1925, there may be used various other yeasts such as Saoohwromyccs ellipsoc'deas and in general any yeast capable of producing glycerin in commercially recoverable amounts.

In the Eofl Patent 1,288,398. it is stated that potassium carbonate or otbenalkaline salts may be used in place of sodium carbon- Y ate. Ordinarily sodium carbonate is, of

course, a very much cheaper source of alkali than potassium carbonate, but in view of recent developments such as that described residue contains the potash salts, and these salts can be recovered by solution in an well-known manner. By adding to the mas undergoing fermentation a solution of the soluble salts present in the above mentioned ash, there may be obtained an excellent yield of glycerin. My investi' ations have shown 1 that normal yields of g ycerin may be obtainedby usin potassium carbonate in solution in place o sodium carbonate, even when the concentration of only 50% in the solution used.

The total amount of sodium carbonate or I other salt added should ordinarily .be between 20% and 35% of the total sugarto be fermented, that is, the sum of'the sugar in the mash initially and the-sugar in the salt solution added during the fermentation. As will be understood, the conditions of operation are not limited to. these ecific values 'ven above, but maybe 'varie oonsiderab y without departing -from my in! v,vention; I

Where the words favorable or optimum are employed in the appended claims potassium carbonate is.

in connection with the concentration of the mash, it is intended to indicate thereby such concentrations as are most favorable to the production of glycerin by the fermentation process as herelnabove described.

I clalm:

1. In that process of producing by the fermentation by yeast of a mash containing a, solution of a yeast fermentable sugar,which includes the addition to the mash, at intervals ,during'said fermentation of successive doses of a material capable o promoting such formation of glycerin, the modification which comprises adding to said mashat intervals during said fermentation the several portions of said material in the form of water solutions thereof, each of said solutions containing such-an amount of sugar dissolved therein that the addition of each of said water solutions will not decrease the ratio of sugar to water in the resulting mesh.

2. The process as set forth in claim 1 in which fermentation is brought about by yeastNo.16.

3. A process as set forth in claim in which the material capable of promoting the material capable of promoting the for-' Mid the formation of glycerin is a salt having an mation of gylcerin is an. alkali-metal carbonate.

5. In the process of producing glycerin by subjecting to yeast-fermentation a black strap molasses solution while adding successive doses of an alkali-metal carbonate totalling from about 20 to of the sugar to be fermented, the step which comprises adding said carbonate dissolved in an aqueous solution containing about 30% of black strap molasses.

6. In the production of glycerin by yeast fermentation of a mash containing in solution an optimum amount of a yeast fermentable sugar and material adapted to promote such formation of glycerin, the process of adding to the undergoing fermentation successive doses of a water solution of said sugar and said material, said doses being added at such intervals during the progress of the fermentation as to substantially maintain the concentration of sugar and material within the'optimum range throughout the fermentation.

7. The process as set forth in claim 6 in which the solution comprising the doses has a sugar concentration substantially equal to that of the mash undergoing fermentation, but a relatively high concentration of material adapted to promote the formation of glycerin. I

8. In the production of glycerin by yeast fermentation of a mash containing in solution favorable amounts of a yeast fermentable sugar and material adapted to promote such formation of glycerin, the process of adding to the original mash during the progress of the fermentation, successive doses of a Water solution of said sugar and said material, said doses being of small volume relative to the original mash but of high relative concentration.

9. In the process of producing glycerin by subjecting to east-fermentation a mash contaming in so ution an optimum amount of the yeast fermentable sugar, the step which comprises adding a material capable of promoting the formation of glycerin, said material being added dissolved in an aqueous solution of a yeast-fermentable sugar, said solution having substantially the same sugar concentration as the fermentin mash.

10. The process as set forth In claim 5 in which fermentation is brought about by yeast N o. 16.

In testimony whereof I aifix my signature.

FRANK A. MQDERMOTI.

,- caRTiFIcATE or CORRECTION.

. above numbered patent requiring correction as follows:

Patent No. 1,725,363.

(Ta-sated mi. 20, 1929, to

FRANK a McDERMOTl.

It is hereby certified that error appears in the printed specification of the Page 3, line 17, claim 6, after the article "the" insert the word "mash"; lines 37 and 38, strike out the words "original ms'sh during the progress of the" and insert instead "mash I j undergoing"; and the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent 0flice. I

' Signed and sealed this 15th day of October, A. D. 1929.

(Sea!) M 3., Moore,

I ;&etinZ-Mssiones of Patenta 

